Process for bleaching foods



UNITED .STATES IRVING HOGHSTADTER, 0F FAR ROCKAWAY, NEW YORK.

rnocrss FOR BLEACI-IING- roons.

No Drawing.

To all whom it may concern:

Be it known that I, IRVING HOCHSTADTER, a citizen of the United States, residing at Far Rockaway, in the county of Queens and State of New York, haveinvented a certain new and useful Process for Bleaching Foods, of which the following. is a specification.

This invention relates to a process for bleaching-foods, and more specifically to a bleaching process wherein sulphur dioxide (S0,) or sulphurous acid or a salt of sulphurous acid is used, and the product then oxidized by hydrogen peroxide (H 0 or other peroxide or peroxide giving compounds non-injurious to food.

Processes for bleaching with SO (which expression is used herein throughout to indicate S0 whether combined or uncombined toproduce other compoundssuch as sulphurous acid, sulphites or bisulphites, etc.) have been known for many years, but it has been a troublesome matter to eliminate the S0 remaining in the food after the bleaching operation has been completed. The federal and various State pure food laws regulate and limit the S0 content in foods, and it is therefore highly desirable to make use of a process which can remove entirely or decrease the amount of such SO without damagin the food.

The invention as accordingly as an object the provision of a process for removing SO from food without damage thereto, and moreover with an improvement in its qualities. It has as an object a process of bleaching in which S0 is used in conjunction with an agent which will assist in the bleaching operation. The invention accordingly relates to a process which comprises treating a food with S0,. and then with H 0 More specificall it relates to such a process wherein the H 6 is added in amounts sufiicient not only to oxigize the S0,, but also to itself bleach the foo The invention relates to the treatment of foods of various kinds generally, but for the sake of a specific description the following embodiment is given Gelatine which has been bleached with SO may befurther treated by hydrogen peroxide (H 0 whereby not only additive efl'ects of both bleaching agents are obtained, but also a combined effect which seems to be due to the bleaching action of the peroxide on substances ordinarily not susceptible to bleaching action by SO or H O but Specification of Letters Patent.

Application filed April 6,

Patented Apr. 11, 1922.

1921. Serial No. 459,088.

which are conditioned by the treatment with SO so that they can be bleached by the subsequent treatment with the peroxide. Moreover, the mere additivev effect of the S0 an H O treatment secures a better bleaching of the gelatine than by the action of either agent alone since one is reducing and the other oxidizing in its action. It is advisable to add from 2 to 4% of ammonium hydroxide (NH,OH) to aid and accelerate the bleaching process with H 0 and in case there should be any acidity in the product this can be neutralized with ammonium hydroxide. The treatment with H O is carried out at a temperature of about 140 to 150 F. As a result of this treatment the sulphur dioxide present is entirely eliminated or reduced to the smallest possible amount, which would not be more than a trace.

As another embodiment of the invention, the following is given I11 the bleaching of cherries, SO may be added either uncombined as a gas or combined as a solution of sulphurous acid or of a sulphite such as sodium sulphite, which may be used in the cold or with the application of a little heat, and this treatment may be continued from one to at hours, according to circumstances. The SO remaining is then washed out with water as much as possible,

and there will be left an amount of SO ranging from mere traces to five to six thousand parts per million. The cherries are then treated with H O in the form of a three to four per cent solution in an amount sufiicientto oxidize the SO to H SO or compounds of the same and also to further bleach the cherries. In this bleaching operation the action is an oxidizing one as contrasted to the reducing bleahhing action of the S0 As a result, in this embodiment of my invention, also, the sulphur dioxide present is entirely removed or reduced to the smallest possible amount which would not be more than a trace.

The sulphuric acid H SO 'and compounds thereof formed in the above processes may be then removed by washing or preferably by treatment with an alkali to neutralize the acid or both. The alkali used may be ammonium carbonate, ammonium hydroxide, sodium carbonate or sodium bicarbonate, sodium hydroxide, calcium hydroxide, or any other alkali which will not be injurious to the food, a volatile alkali being particularly suitable since it can evaporate and leave bleaching operation beginning with a reducin bleaching action and ending with an oxidizing bleaching action so that any decolorizing substance present in the food which Wlll respond to an oxidizing or reducing action will be effectively attacked and bleached.

A large number of other foods may be similarly treated, such as fruit products,

syrups, nuts, potatoes, apples, cereals, and in fact any kind of food susceptible to such treatment. The treatment of fruit products by this method is particularly desirable since a bleaching operation is generally necessary and must be thorough in order to make the goods marketable. For example, in the drying of apples the latter are cut into slices and then put into an evaporating chamber through which hot air at about 155- F. is passed in a careful manner to remove all but a small per cent of the water. During this operation the oxygen of the air is very likely to cause the apples to discolor, and'it isnecessary to bleach them to make them white. If the bleaching operation is not effective in retaining the white color, the apples cannot command as high a price on the market as pure white dried apples. The same is true of dried sliced potatoes. By the treatment of this invention, the white color is made permanent and the S0 at the same time removed.

Any H O which remains in the foods does no harm since it breaks up to form water and oxygen as very rapidly.

By the term S5, either sulphurous acid, a salt thereof, or an SO producing composition, and by the term H O I mean hydrogen peroxide, a metallic or other peroxide, or a peroxide giving composition non-injurious to foods.

As many apparently widely different embodiments of this invention may be made Without departing from the spirit thereof,

it is to be understood that I do not intend 1.' The process which comprises treating a food with S0 and then with H O unmixed with additional acids. I

in the claims I mean 2. The process which comprises treating a food with S0 and then with H O unmixed with additional acids in sufiicient amount to oxidize the S0 3. The process which comprises treating a food with S0 and then with H 0 and neutralizing the acid oxidation product formed with an alkali.

4. The process which comprises treating a food with S0 and then with H O in sufficient amountto oxidize the S0 and neutralizing the acid oxidation product formed with an alkali.

5. The process which comprises treating a food with S0 washing in water to remove some $0,, and then treating with H 0 6. The process which comprises treating a food with S0,, washing with water to remove some 30,, then treating with H 0 and neutralizing the acid oxidation product formed with an alkali.

7. The process of removing SO from a food bleached thereby, comprising treating it with H O in quantities sufficient to oxidize the S0 and then neutralizing the acid oxidation product formed with a volatile alkali.

8. The process of bleaching a food complrising treating it with S0 and then with 0 in amounts suflicient to oxidize the S0 and to further bleach the food.

9. The process of bleaching a food comprising treating it with S0 washing with water, and then treating with H O in amounts sufficient to oxidize the S0 and to further bleach the food.

10. The process of bleaching a food comprising treating it with SO and then with H 0 in amounts suflicient to oxidize the S0 and to further bleach the food, and neutralizing the acid formed with an alkali.

11. The process of bleaching a food compfising treating it with S0 and then with.

0 in amounts sufficient to oxidize the S0 and to further bleach the food, and then neutralizing the acid formed with a volatile alkali. v

12. The process of bleaching a food comwater, and thentreating with H O in amounts sufiicient to oxidize the S0 and to further bleach the food, and neutralizing the acid formed'with an alkali.

13. The process of bleaching gelatine comprising treating the gelatine with S0, and then with H 0 14. The process of bleaching gelatine comprising treatin the gelatine with S0 and then with H 2 in the presence of ammonium hydroxide.

In testimony that I claim the foregoing, I have hereunto set my hand this 21st day of March, 1921.

IRVING HOCHSTADTER. 

